In the production of metal products it is often necessary to permanently stamp important information into the surface of the product. For example, large metal tubes or pipes used in the power generation industry must have a series of characters permanently imprinted therein for identification purposes. Such identifying characters are generally applied by hardened stamps similar in appearance to printing type, but capable of being punched into the metal surface. Each stamp can include one or more characters, and are struck directly by a hammer or the like to punch the character or set of characters into the metal. Where the identification must include a series of individual characters, however, aligning and punching in the characters individually can be a time consuming process, and it is difficult to maintain uniform spacing and alignment of the characters. Devices for holding several individual stamps are known; however, they are generally designed to imprint all the characters at once, and particularly when imprinting steel piping it is difficult to obtain a sufficiently deep imprint.
Another problem associated with prior art devices is that of positioning a stamp holder on a rounded surface such as a large steel pipe.